Jewelry may contain traces of nickel, chromium, copper and other such irritant metals which cause an allergic reaction. This may also be a sign of secondary infection. Since cartilage has a relatively poor blood supply, high doses of strong antibiotics are required, if the cartilage underlying the ear skin is affected. Switch to pure gold 24K wire / earrings for now and take medical treatment (antibiotics, anti-inflammation, anti-allergy agents and painkillers) under supervision of a doctor. Local ointments and dressings will also be required.